As per my previous thread about the amp suddenly developing a hiss sometimes and violently flapping the mid-bass driver on the speaker, even when no music played but all components on ( coming out of the right channel only ), i collected the amp last night after work. The techie guy who had the amp for 2 weeks said that he did every test he could think of, ran hot for 10 hours then cooled down, took it apart to test every component etc etc, conclusion is that the amp is perfect, running fantastic, checked it with Sugden,s technical specs and it has not dropped or lowered in any way since the day it left the factory, in fact the guy was very impressed, ( unlike the guys at sevenjokes who described it as a toy amp, but hey ) For this he charged me £50, fair enough, have to pay for his time. Now the problem could be the pre-amp or further up the chain, he thinks, have had it running since last night and it still sounds great. Just thought i would keep you guys updated, John.